Examples of appearance changes caused by skin aging include formation of wrinkles and sagging and reduction of skin firmness. Until now, cosmetics containing, for example, collagen have been used for improving such appearance changes of the skin. However, even if such cosmetics are used, the effect of inhibiting (suppressing) wrinkle formation or the like is insufficient.
Formation of wrinkles or the like is considered to have a strong association with ultraviolet rays. Skin aging caused by irradiation with ultraviolet rays is referred to as “photoaging”, and a variety of studies have been made. However, the present situation resides in that a cosmetic, which can be used as an alternative of an ultraviolet absorber or an ultraviolet protectant in order to prevent the photoaging, has not yet been developed.
On the other hand, Japanese Patent No. 3549823 discloses an agent which contains alverine and is useful for reducing wrinkles and fine wrinkles. Specifically, Japanese Patent No. 3549823 discloses that alverine can induce a decontraction and/or relaxant effect in the striated muscle, and the effect can repair wrinkles and fine wrinkles and promote smoothing of the skin. However, alverine is used as a muscle relaxant in Europe based on its acetylcholine-blocking action. Alverine has been used as a drug and has high toxicity (refer to, for example, David Malka et al., Journal of Hepathology, 1997, vol. 27, p. 399-403).
Moreover, JP-A-2005-528323 (“JP-A” means unexamined published Japanese patent application) and JP-A-08-333217 disclose agents for external application to skin which are used for improving and preventing appearance changes such as wrinkles of the skin. The agents for external application to skin described in the documents can improve and suppress epidermal wrinkles (for example, wrinkles caused by drying) due to aging of epidermal cells of the skin. However, the effect for deep and stubborn wrinkles produced in dermal cells or cell tissues located deeper than the dermal cells is insufficient.
As described above, a photoaging-preventing or -improving composition or a wrinkle-preventing or -improving composition, which can be used safely and has a sufficient effect, has not been known.